Installing A Marine Electrical Panel In A Day

Prior to purchasing Beach House, we had a thorough survey done by Bob Dulce from Hilton Head South Carolina. Bob knows the Marine Traders intimately, as he has been involved with them since the first hull was imported into the U.S. He is also an excellent and knowledgeable surveyor that understands what can happen when a survey reaches an insurance company with a lot of "recommendations." They immediately become "requirements" as soon as a clerk at the insurance company sees them. So items that were not major, but needed attention at some point, were made known to us during the survey, but did not find their way on to the final report. One of those items was an electrical panel that a previous owner had installed in the hanging locker for the forward cabin. As was the practice during the late 70s and early 80s, a household electrical panel had been installed to service the added air-conditioner, some 120-volt lights and an added outlet in the engine compartment. The panel was in good shape and wired correctly so there was no urgency to replace it immediately. So it went on our to-do list. In time, it finally rose to the top of the list, and the weather cooperated so that neither the heat or the air-conditioning would be needed for an entire weekend--plenty of time to complete the project. So it began.

The first item of business was to find the appropriate spot to mount the panel. We had considered putting the new one back inside the locker where the old panel had been. It was out of the way and the wiring was already there, a tempting prospect. But it was also a pain having to go in the locker behind all of the hanging clothes, we could not see to monitor the gauges and breakers, and we did not like having clothes hanging right next to an electrical panel. Outside the locker did not leave a lot of options. The panel needed to be accessible, yet not in an area where it could get bumped and the breakers accidentally turned off. At first glance, we ruled out anywhere on the front of the lower helm station. But after some study, we decided that this would actually be a good spot since we had instant access, and by putting it high enough and slightly behind the wheel, we would have to try very, very hard to bump it or come in contact with the panel so as to be a problem.

The next step was to cut the hole to fit the connections and breakers that stick out from the back of the panel. We chose the Blue Seas panel because we knew from past experience it was of good quality. They provide a template with the panel to make cutting the hole easier. An important issue is to be sure there are no wires, plumbing or anything else that will interfere with the mounting on the back side of the bulkhead. We used the template on the inside to determine where the panel would be mounted by tracing it on the inside wall, then drilling small holes in the corners. We could then transfer the template to the front of the bulkhead by using the small holes as a guide. The entire area where the panel was to be mounted is covered with easy release blue tape, and then the template is drawn on the tape with a fine tip marker. I like to drill holes in the corners with either a small hole saw of drill bit large enough to accept the blade for my jigsaw. Once this is finished, the hole is carefully cut for the panel and all of the sawdust vacuumed. In addition to replacing the panel, we were also replacing the shore panel outlet mounted on the outside cabin side. The old outlet was plastic, quite old and beginning to deteriorate. This is actually what started us on this project. The new stainless outlet would match the other Marinco outlet that we had previously installed. 

The panel is put in place to be sure it will fit the cut out, and to make sure it is straight and not mounted on an angle. It is also the time to check that all of the wiring that needs to be connected will reach the panel and be clear of obstructions in the back. Any slight trimming of the cut out or a little sanding to make a better fit can be done now. 

With the hole cut and the tape removed, the holes are drilled slightly smaller than the screws that will hold the panel in place and the fitting checked one more time. There is usually lots of sawdust and debris on both sides of the bulkhead, so a good vacuuming and wipe down is in order. We usually like to take this time to sand and varnish the area around where we are doing the work to avoid taking everything apart later.

Before doing any work on the boat's electrical system, the power must be turned off at the breakers on the dock and the shore power cords disconnected. The old shore power outlet was removed, and as is our practice, the core material around the cut out is sealed with West System, and then a thickened epoxy is used to fill in uneven spots and holes. The epoxy is sanded smooth before the outlet is installed. This insures that any leaks will not work their way into the core and cause rot and other problems. Even the screw holes get an injection of epoxy.   

The new outlet is installed, and even with the gasket provided from the manufacturer, we use additional sealant to prevent water intrusion. Everyone has their favorite brand, but we like to use SikaFlex for most of these projects. Prior to re-installing the outlet, it is wired with long enough wire to reach the new panel. This panel would feed the air-conditioner, hot water heater, a few outlets and 110-volt lights. It is a fairly heavy load, so care needs to be taken in using the proper wire size. I used a #8 wire on both of our outlets to connect to the panels, even though the run from the outlet to the panel is only a couple of feet. The green earth grounds from both outlets go into our galvanic isolator and then to the panels. The hot and neutrals go directly to the main circuit breaker for each panel.

The wiring can be done with the panel in place from the back, or in some cases I prefer to connect up everything before the panel is put in place if there are not too many connections. I would add a word of caution here. Unless you have a complete understanding of the proper methods for wiring a boat, I highly recommend you hire a professional. I have been doing this for many years as a profession, so it is fairly simple for me. The wrong connections or improper installation can have catastrophic consequences. Once all of the connections are made and the panel secured in place, all of the wiring needs to be secured. We tend to use lots of wire ties and wire straps to keep everything neat, organized and from moving around, which can cause connections to come loose and wire to chafe through. 

This time, because of the time it would have taken to make some repairs to the wood and varnish the surrounding areas, we did not refinish. That will get done later. With everything in place and all connections tested to be sure they were secure and tight, it was time to connect the shore power. Our practice is to make sure everything on both panels is turned off. The dockside breaker is also turned off, and the shore power cords are plugged in at the dock and the boat. The next step is to turn on the breaker on the dock, and check the voltage meters on the panel for proper voltage. The reverse polarity lights should not be on on either. If they are, something is wrong, and the power should be turned off immediately. If all goes well and looks good, the circuit breakers on the panels should be turned on one at a time, waiting a brief moment between turning each on. Watch the voltage meter for sudden voltage drops, since this could mean a short or other problem. Watch the reverse polarity light as each breaker is turned on. If everything was done correctly, the appliances, etc. can now be switched on. This is a small, relatively simple panel, but if a larger panel with more complicated wiring and DC breakers are included, a much more comprehensive approach is needed. But if a small auxiliary panel is needed, this will get you back in business without a great deal of expense. If you are not sure of your abilities, get the advise of a professional.